Automatic reclosing circuit breaker



V- 4, 1953 J M. WALLACE ET'AL 2,660,636

AUTOMATIC RECLOSING CIRCUIT BREAKER Filed July 5, 1951 2 Sheets-Sheet l Fig.|.

Insulation Insulation Insulation WITNESSES: INVENTORS 477 James M.Wolloce vand Albert P. Sfrom.

Nov. 24, 1953 J. M. WALLACE ETAL AUTOMATIC RECLOSING CIRCUIT BREAKER 2 Sheets-Sheet 2 Filed July 5, 1951 m S r 29 E N H @MGS 4 W 0 W M 4 4 5 WM n V a 6 62 4 am A 8 61 5 mdfl 4 4 O 3 J Y 4 2 B my 6 5 M% F 6.\.: l Bah L W V 7//// Q 9 O 6 6 3 5 6 G 8 4 6 5 Fig.2.

WITNESSES:

ays/$15,. 211

Patented Nov. 24, 1953 AUTOMATIC RECLOSING CIRCUIT BREAKER James M. Wallace and Albert P. Strom, Pittsburgh, Pa., assignors to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Application July 5, 1951, Serial No. 235,281

19Claims. 1

Our invention relates generally to automatic recl'osing circuit breakers, and it has reference in particular to circuit breakers of this type wherein a fluid or gas under pressure is used to operate the circuit breaker and extinguish the are formed during a circuit interrupting operation.

Generally stated, it is an object of our invention to provide in a fluid pressure operated circuit breaker for determining the number of circuit interrupting operations before the breaker is locked open, by means of the amount of pressure fluid in the container supplying the breaker.

Another object of our invention is to provide in a compressed gas operated circuit breaker of the reclosing type, for utilizing time delay means to delay-operation of the breaker, and for utilizing means responsive to the pressure of the gas in the circuit breaker tankfor rendering the time delay means ineffective for the first one or two in the open position when the pressure in the breaker tank drops to apredetermined operating value.

Still another object of our invention is to provide in a reclosing circuit breaker for utilizing brake means responsive to pressure differentials in the operating means, for delaying reclosing of the breaker after av circuit interrupting operation.

.It isalso an object of our invention to provide in an automatic reclosing circuit breaker of the compressed gas actuated type, for mounting the breaker and its operating mechanism in a container which has sufficient capacity to store compressed gas for obtaining a predetermined number of breaker operations, and for utilizing pressure responsive means to thereupon eiiect a locking of the breaker in the open position, if the fault causing operation of the breaker persists.

These and other objects of this invention will become more apparent upon consideration of the following detailed description of a preferred em bodiment thereof, when taken in connection with the accompanying drawings, in which:

Figure l is an elevational view, broken out in 2 part and partly in section, illustrating a circuit breaker embodying the principal features of the invention;

Fig. 2 is an enlarged cross-sectional view of the upper or interrupter portion of the circuit interrupter shown in Fig. 1

Fig. 3 is an enlarged sectional view of the lower or actuating portion of the circuit interrupter shown in Fig. l; and

Fig. 4 is an enlarged sectional view, in part, of the actuating portion, showing the brake in the set position.

Referring to Fig. 1 of the drawings, the reference numeral Ill may denote generally a complete circuit breaker of the compressed gas type embodying the features of the present invention. The circuit breaker may comprise a tank or container l2 for storing compressed gas for operating the breaker and for also enclosing and protecting the breaker'mechanism 13. The breaker mechanism [3 may comprise generally fluid actuated means I4 for operating a breaker contact mechanism which may be enclosed in an interrupter structure I6 mounted on the fluid actuated means. Operation of the fluid actuated means may be controlled by a valve mechanism It disposed to be controlled by a solenoid operating means 20 including a solenoid coil 2! associatedtherewith.

The tank l2 may comprise a cylindrical steel side wall structure 22 having flanges 23 and 24 at the ends for securing top and bottom cover plates 25 and 26' thereto by means of bolts or the like (not shown). Electrical connections may be made to the circuit breaker by means of insulating bushings 28 and 29 which may be secured in openings in the top cover plate 25, and conductors 30 and 3| which connect to an intermediate portion of the breaker mechanism and to the operating solenoid 2|, respectively.

Compressed gas, such as air or carbon dioxide, or the like, may be supplied to the tank 22 through a needle valve 32 at a rate which is merely sufficient to restore the pressure in the tank after an operation, and is not suiii'cient to actually supply gas at the rate at which it Will be used during a circuit interrupting operation. A solenoid-controlled valve 34 may be provided for venting the tank for reasons which will be explained hereinafter.

Referring particularly to Figs. 2 and 3, it will be seen that the fluid actuated means 14' may comprise: a cylindrical tube 360i insulating material, such asfiber orthe like, having a peripheral shoulder 381 intermediate it's ends. The; tube aceacsc 36 may be mounted in the bottom cover plate 26 by means of a split ring Bi which engages the tube adjacent the shoulder 38, and an as sociated clamp ring fill which may be connected to a ring 42 secured to the cover 26 about opening 44 through which the lower portion of the tube 36 projects. A. gasket 45 may be disposed between the shoulder 38 and the ring 42 for providing a seal therebetween.

A piston 46 may be slidably disposed within the inner bore 41 of the tube 36, having a contact rod 48 secured thereto for actuating one of the breaker contacts. A spring 50 may be disposed in the lower section of the tube 355, bein retained therein by a cover 52, for normally ing the piston $6 to a contact closing position. The piston 46 may be provided with an annular groove 54 disposed to be connected by a passage 56 with the bore All of the insulating tube.

Ports 5'! may be provided in the side Walls of the tube 36 at a point slightly below the cover plate 26 for venting the bore when the groove 54 of the piston traverses these ports.

Brake means may be provided. in conjunction with the piston 45 for not only stopping the pis on when it traverses the ports 51, but also retarding the restoring action of the spring 58 to return the piston to the closed contact position after circuit interrupting operation. The brake 60 may comprise a flexible and resilient toroidal. i

brake member 52 of rubber or the like, having channel-shaped section and loosely disposed in an annular groove 64 so as to provide an annular chamber 65 into which the gas may be admitted through clearances between the brake member 62, the walls of the bore 41, and the of the groove 54. An orifice $5 and a needle valve *3? permit release at a controlled. rate of the pressure fluid trapped in the chamber to provide a timed braking action when the cylinder is vented. A latch 68 may be provided for engaging the pieton 45 through an opening 69 in the tube 35 to lock the breaker in the open position under predetermined operating conditions, as will be explained hereinafter. The latch may be pivotally mounted on the cover plate 26 by means of a pivot 1!], and biased into piston engaging relation by means of a spring 12.

The interrupter l5 may comprise a cylindrical insulating body M of porcelain or the like having flanged end rings l5 and 16 secured thereto in any suitable manner as may be seen by referring particularly to Fig. 2. The interrupter may be mounted on the insulating tube 36 by means of a split ring l'fl which engages the upper end or the insulating tube 35, and a wedge ring 19 to which the end. ring 15 may be secured by means of bolts 80. A gasket 32 may be disposed between the insulating tube 36 and the end ring It? to provide a seal, and a condenser 83 of expanded metal may be disposed in the end ring for cooling gases passing from the interrupter to the fluid actuated means.

Inside the interrupter iii a movable contact 84 may be mounted on the contact rod 48 for engaging a stationary contact 86. The moving con tact 84 may be electrically connected to the end ring 16 by means of a flexible helical shunt 38 for effecting connection to the conductor 30. The stationary contact 85 may be suitably supported in the upper end of the interrupter it being, for

'example, threadedly secured in a boss 96 depending from a valve plate 92 supported on the upper end of the interrupter. The boss 50 may be provided with a plurality of orifices 93 suriii) operating coil 2!.

rounding the stationary contact 86 for permitting the flow of compressed gas therethrough. Immediately surrounding the junction of the stationary contact 86 and the moving contact 84 is an arc chamber 94, which may be provided by securing a cup 95 of insulating material, such as fiber, a refractory, or other suitable are resistant material, to the dependent boss 90. The cup 95 may be provided with a suitable orifice 9T surrounding the movable contact 84 so as to provide for a blast of compressed gas for extinguishing any are drawn between the contact members.

The valve mechanism It which controls the how of compressed gas for effecting operation of the breaker may comprise a flexible diaphragm 99 of natural or synthetic rubber or the like, providing the main element. The diaphragm 98 may be mounted on the valve plate 92 which has central orifice Iliil for admitting gas to the interrupter and operating mechanism. The valve plate 92 may be provided with an annular rim Hi2 surrounding the central orifice I00 so as to define an annular chamber 104 between the valve plate and the diaphragm. A plurality of orifices )5 in the valve plate connect the annular chamber Mi -l to the main body of compressed gas in the tank !2. The diaphragm 99 may be provided with a pilot valve comprising a movable valve stem iii! having a pilot valve member l 10 thereon for closing a pilot orifice H2 in the diaphragm, in its lowermost position, and blocking the valve stem opening H3 in its uppermost position, to seal off the above the diaphragm 99. A spring i it normally biases the valve stem I0! to close the pilot orifice H2. The diaphragm 99 may be secured to the valve plate 92 by means of a cap H8 which may be secured to the upper end ring iii of the interrupter by means of bolts Operation of the valve stem it? may be effected by means of a cylindrical core member H6 which may be slidably disposed on the stem and disposed to be actuated by the solenoid The operating coil 2! may be disposed in a substantially U-shaped frame I l! which may be secured to the cap I 18 by means of screws H9 and spacers I20. A sleeve 122 having a flange !23 at its upper end may be threadedly secured to the core H6 at its upper end and slidably disposed on the valve rod I07. Operation of the valve rod may be effected by means of a pin K25 which projects transversely of the valve rod and is disposed to project through slotted openings I21 in the sleeve. Upon a predetermined movement of the sleeve in response to energization of the solenoid coil 2!, the pin [25 will be engaged by the bottoms of the slotted openings for actuating the valve stem 2 c1 to open the pilot valve H0 and close the opening H3.

In. order to operate the valve stem (01 so as to effect operation of the fluid actuated mechanism [4 for locking the circuit breaker in the open position, pressure responsive means, such as the bellows device 13c, may be provided. The bellows device I36 may be provided with a spring E32 disposed to expand the bellows device against the compressive action of compressed which surrounds the bellows device within the tank l2.

The bellows device may be suitably mounted on a lower portion of the frame H! of the solenoid coil 2|, and provided with an extension (34 for effecting operation of a lever I38 which may be pivotally mounted by means of a pivot :33 on the insulating tube 36.

a substantially U-shaped support I40 mounted on the upper side of the =.c.oil supporting frame H11. The lever 136 may be provided with an opening for receiving the upper end .of the valve stem I0! which may be provided with locknuts I42 to provide for lifting the valve stem when the lever +36 is rotated .in a clockwise direction. The extension I34 of the bellows .de-

vice I36 may be provided with a transverse zp'in .may be disposed in the dashpot and secured to thelower end of the core I I6 for retardingrmove- -ment thereof. The dashpot may be filled with .a suitable liquid, such as 'oil or the likaandpro- 'vided with a. cover 156 having sandwiched therein gasket material, such as cork 58, for substantially enclosing the dashpot. .In order to provide for an initial one or two relatively fast circuit interrupting operations, means, such as the lever I66, may be provided for initially rendering the time delay means 58 inoperative.

The lever I50 may be pivotally mounted on the support I40 bymeans of a pivot IGZ-anddisposed to engage the flange 123 for lifting the core I Hi sufficiently to -separate the suction disc lfiilfrom the bottom ofthe-dashpot. This result maybe accomplished :by having the ,pin M4 on the bellows extension device I36 engage the .lever I60 to rotate it in a-counterclockwise direction'when the pressure in the circuit breaker tank l2 is sufiiciently high, as it will :be during the initial one or two operations.

Initially, the pressure in the circuit breaker tank l2 will probably .be on the order of '100 p. s. i. Upon the occurrence of anzoverload, the solenoid coil 2I is sufficiently energized to attract the core II6 upwardly. Because the pressure in the tank I2 is sufiiciently high, the :bel-

:lows device I36 will be compressed sufficiently,

so that the pin I44 is engaging the lever 1.60,

:and the core H6 will therefore be initially lifted sufficiently that the dashpot suction disc 1:54 ;is

separated from the bottom of the :dashpot, and

the .dashpot is therefore inoperative to :delay movement oi the core H 6. Accordingly, the core I I6 is lifted rapidly, and raises the valve :stem I01, thus opening the pilot valve .Hi) and 1010sing the opening .IIS. This causes the pressure immediately above the diaphragm 19.9 to drop to substantially atmospheric pressure which is the pressure in the orifice 4'00, and the bore :41 of Since full tank pressure is applied to the lower surface of the diaphragm '98 in the annular space I64, the'main valve diaphragm S9 lifts. and tank pressure "is admitted to the interrupter l6 through "the ori'fice I116. Pressure on the piston 46 forces it downwardly, thus separating the moving contact 84 from the stationary contact 66. Pressure builds up behind the piston 46 and gas flows into the space 65 behind the toroidal brake member '62. As soon as the piston traverses the ports 51, the

bore of the insulating tube 36 'is vented to the atmosphere, thus permitting gas from the "tank :I2 to flow rapidly through the arc chamber :94 and extinguish the arc. .As soon as the annular groove 54 of "the piston 46 :reaches the ports 25.7, the pressure in'the bore 4'? is greatly reduced. Gas .in theannular chamber 65 behind the brake member 62 thereupon expands, vsealing the flanges of the brake member 6.2 against the sides of the groove 64, :as shown 'in Fig. .4, and :forcing the brake member :against the inner 'wall of the tube 36. This not only assists in stopping downward'motionof the piston 46, but fitalso retards the return motion, thus permitting .the contacts to remain .separated, :even though the arc has been extinguished and the pilot vaive I I 0 has been .released, whereupon the pressure from the tank builds up in the space on thezupper side of the diaphragm :99, being admitted through the clearance around the valve :stem J61, causing'thediaphragm to.immediately seal against the :rib I02 to terminate the fiow of gas through the interrupter. The gas in the annular chamber6z5 leaks out slowly at a rate which maybe determined by "the setting of the valve :screw .67, when the gas pressure .in chamber 65 drops sothat-the starting'friction of :brake .69 is less than the restoring force of spring 56, the piston will start to move, and once started, will accelerate to close the :contacts'with snap action.

Should the fault persist, 'a second interrupting operation will take place similar to that'described. In the event that the fault stillptersists,

a third interrupting operationwill follow. This against the bottom .of the :dashpot. This-renders the :dashpot effective to delay lifting of the pilot valve III] and thus delay the circuit opening :operation. Atter thesuction disc I54 has been separated from the bottom of the dashpot in response toxactuation of the core :II.6,-the pilot valve .I'ID'willbe opened, :and the fluid actua'tedmeans will :operate 'ItO separate the contacts "in :8,.ll.l8,l1-

:ner'similar to that described hereinbefore.

In :order to lock the breaker open after .a predetermined number of circuit interrupting operations, 'for example, :after :the fourth operation, the bellows device "I30 :is disposed :to expand sufiiciently in response to a reduction in ithe'pressurein the circuit breaker-tank I2, so that :upon the fourth operation the 'pin I'M will have reached a position wherein it engages the clip i246 and will ibeifDlCfid sideways bythe clip so as .to engage the :lever I35. Upon opening of :the pilot valve H6 by core H6 in :responsezto energization of the solenoid coil 2I for the fourth circuit interrupting operation, the operation-will be substantially identical with that 'hereinhefore describedexceptthat the 'pilot valve l I 6 will "now he heldopen by the lever IEGbeing rotated in a clockwise direction about the pivot I 3.3 due to the:furtherreductionin pressure'in the'tank and the further expansion of the bellows device I30, instead of reclosing immediately upon interruption :of "the arc. Accordingly, when the piston 4.6 reaches the position in which the annular groove '54 ventsthe interior of the insulating tube 36 to the atmosphere and the brake 62 stops the piston 46, gas will continue to flow through the interrupter and fluid actuating mechanism. After the pressure in the annular chamber 65 is reduced sufficiently so as to be equal to the gas pressure of the bore 41, thus releasing the brake 62, the gas pressure remaining in the bore 4! of the insulating tube 36 will still be suflicient to force the piston 46 further down past the ports 51, so that the latch. 68 will be disposed in the annular groove 54, thus locking the piston with the contacts in the open position. As the pressure in the tank l2 decreases still further, the bellows device I30 continues to expand, and eventually the pin I44 passes and becomes clear of the clip Mt. This releases the lever 136 since the extension I34 will be restored to its normal center-line position, in which position the pin M4 is clear of the lever I35. The pilot valve H is thereupon closed by the restoring action of the spring H4, and pressure builds up on the upper side of the diaphragm 99 so as to seal the diaphragm against the annular rib or projection I02 and terminate the flow of compressed gas through the interrupter and fluid. actuated means. Pressure in the tank [2 will thereupon be slowly restored to normal from the source through the needle valve 32. The circuit breaker may be reset by operating the latch St to release the piston 46, which will then be returned to the contact closing position under the influence of the spring 50.

Tripping of the circuit breaker may also be provided by operating the shunt trip valve device 34 either locally or remotely through suitable control switch means, of any well known type, for venting the tank E2 to atmosphere. The resultant pressure drop in the tank effects operation of the circuit breaker by reason of the bellows device I actuating the lever I36 to open the pilot valve H0, whereupon the breaker will be operated to the locked open position in the manner previously described.

From the above description and the accompanying drawings, it will be apparent that we have provided an automatic reclosing circuit breaker in which the compressed gas is both the operating medium and the arc-extinguishing medium. By utilizing a common tank for onclosing the breaker mechanism and containing F the compressed gas for operating the breaker, a simple and inexpensive structure is provided. Such a circuit breaker is self-contained, in that all the compressed gas needed for a complete operating cycle is contained within the immediate circuit breaker tank, thus protecting the breaker against failures in the air supply system. By utilizing pressure means for not only controlling the operating time of the breaker but also effecting the lockout operation, a circuit breaker embodying the features of our invention fails safe, since a loss of compressed gas will cause the breaker to lock open.

Since certain changes may be made in the above described construction, and different chi-- bodiments of the invention may be made without departing from the spirit thereof, it is intended that all the matter contained in the above description and shown in the accompanying drawings shall be considered as illustrative, and not in a limiting sense.

We claim as our invention:

1. An automatic reclosing circuit breaker comprising, separable contacts, fluid actuated means for separating said contacts, fluid storage means containing only sufiicient fluid for effecting a predetermined number of closely successive separations of said contacts, means responsive to a predetermined circuit condition for supplying fluid to said actuating means from said storage means, said contact means being biased to close following a contact separation, means responsive to a reduction of pressure of fluid in the storage means to a predetermined value for eflecting locking of the contacts in a separated condition after a plurality of closely successive contact separations, and means operable to release said contacts from said condition to reclose the breaker.

2. An automatic reclosing circuit breaker comprising separable contacts, fluid actuated means operable to effect separation. of said. contacts, fluid storage means containing only suflicient fluid for a limited number of closely successive operations of said fluid actuated means, electroresponsive means operable in response to a predetermined value of current to effect connection of the fluid actuated means to the fluid storage means, time delay means operable to delay separation of said contacts, and pressure means selectively operable to render the time delay means ineffective and efiective in accordance with the pressure in said storage means.

3. An automatic reclosing circuit breaker comprising, separabie contacts, fluid actuated means for separating said contacts, fluid storage means for storing only suflicient fluid for a limited number of closely successive operations of the fluid actuated means, means responsive to a predetermined condition of a circuit for supplying fluid from said storage means to said fluid actuated means, and means responsive to the pressure of the fluid in the storage means operable when the pressure drops to a predetermined value to eflect locking of said contacts in the separated position to effect no more than a predetermined number of closely successive contact separations if said predetermined circuit condition persists.

4, In automatic reclosing circuit breaker, separable contacts, fluid actuated means for separating said contacts, fluid storage means, means responsive to a predetermined condition of a circuit for connecting said fluid storage means to said fluid actuated means, and pressure actuated means responsive to a drop in pressure of the fluid in said storage means to a predetermined value for eflecting a locking operation of the contacts in a separated position.

5. An automatic reclosing circuit breaker com prising, separable contacts, fluid actuated means for separating said contacts, a container for said breaker having fluid under pressure therein for operating said fluid actuating means, valve means operable to supply fluid to said container at a predetermined maximum rate, means responsive to a predetermined condition of a circuit for supplying fluid. from said container to said actuating means at a rate in excess of said predetermined maximum rate, means responsive to a drop in pressure of the fluid in the container to a predetermined value for effecting operation of the actuating means for locking said contacts in the separated position when the pressure of the fluid reaches a predetermined minimum value, and means for reducing the pressure in the container to effect a locking operation of said contacts.

6. An automatic reclosing circuit breaker comprising, separable contacts, fluid actuated means operatively connected to at least one of said contacts for separating said contacts, a container for fluid under pressure housing the contacts and fluid actuated means, fluid actuated valve means operable to supply fluid from the container to said actuating means, and means responsive to a predetermined circuit condition operable to effect operation of said valve means.

7. An automatic reclosing circuit breaker comprising, separable contacts, fluid actuated means operable to eflect separation of said contacts, a container for said contacts and fluid means containing fluid under pressure, a diaphragm valve controlling the supply of fluid from said container to said actuating means, a pilot valve in said diaphragm for eiiecting a flow of fluid to actuate said diaphragm, means responsive to a predetermined circuit condition for operating the pilot valve and thus controlling the supply of fluid to said actuating means for separating said contacts, means operable to close said contacts following a separation, and delay means preventing closing of said contacts for a predetermined time.

8. An automatic reclosing circuit breaker comprising, separable contacts, fluid actuated means operable to separate said contacts, means re- 'sponsi've to a predetermined circuit condition to admit fluid to said fluid actuated means for efi'ecting separation of said contacts, time delay means operable to delay separation of said contacts, pressure means operable to render the time delay means ineffective on predetermined operation of the fluid actuated means, means biasing said contacts to reclose after separa tion, and additional means operable only after is separation of said contacts to delay reclosing thereof.

9. In an automatic reclosing circuit breaker, relatively movable contacts, an arc chamber for receiving said contacts, fluid actuated means operatively connected with one of said contacts for separating said contacts, said fluid actuated means being connected by a passage with the arc chamber, electroresponsive means responsive to a predetermined circuit condition for supplying fluid under pressure to said are chamber and fluid actuated means, means operable to reclose said contact, and brake means operable in response to the termination of supply of fluid to the fluid actuated means to maintain the con- I tacts separated for a predetermined time before permitting reclosing.

10. In an automatic reclosing circuit breaker, separable contacts normally biased into engagement so as to reclose automatically following a circuit interrupting operation, fluid actuated means for separating said contacts and eXtinguishing an arc, a container for fluid under pressure containing said contacts and fluid actuated means, means supplying fluid to said container at a predetermined maximum rate, valve means controlling the admission of fluid from said container to said fluid actuated means at a rate in excess of said maximum in response to a predetermined condition of a circuit through said contacts, and means responsive to a predetermined reduction in pressure in the container controlling said valve means to effect operation of the fluid actuated means to separate said contacts.

11. An automatic reclosing circuit breaker comprising, separable contacts, means normally biasing said contacts together, fluid actuated means for separating said contacts, a fluid container enclosing said contacts and fluid actuated means, said container containing sufficient fluid under pressure for effecting a plurality or closely successive separations of said contact means, means responsive to a p'redeterminedcircuit condition for admitting fluid to the fluid actuated means from the container, means forrcplenishing the supply or fluid in the container at'a rate much slower than it is supplied to the fluid actuated means, pressure responsive meansoperable to lock said contacts separated when the pressure in the container reaches a predetermined minimum value.

12. An automatic reclosi'ng circuit breaker comprising, separable contacts, fluid actuated means for separating said contacts, means for biasing said contacts to reclose them, means responsive to a predetermined circuit condition for admitting fluid to said fluid actuated means, brake means operable to retard operation of said fluid actuated means, and means responsive to predetermined pressure conditions for admitting suflicient fluid to said fluid actuated means for effecting further operation of said fluid actuated means for looking sa idcont'act's open.

13. An automatic reclosing circuit breaker comprising, separable contacts, fluid actuated means operable to separate said contacts, a container for said contacts and actuating means having sufficient fluid therein under pressure for effecting a plurality of operations of the fluid actuated means to separate said contacts, valve means operable to admit fluid to the container at a predet'ermined maximum rate, valve means operable to admit fluid from the container to the fluid actuated means at a rate in excess of said maximum, means responsive to a predetermined circuit condition for operating said second mentioned valve means to effect separation of said contacts, means for reclosing said contacts after such an operation, and pressure means responsive to a reduction in pressure in said container to a predetermined value for effecting operation of the valve means to separate the contacts and render the reclosing means ineffective.

14. An automatic reclosing circuit breaker comprising separable contacts, fluid actuated means including a piston movable in a cylinder for separating said contacts, said cylinder having a port disposed to be traversed by said piston for venting the cylinder when the piston has travelled the distance necessary for a normal separation of said contacts, latch means for locking the piston in a more advanced position beyond said port, a fluid container, valve means for admitting fluid to the cylinder from the container, means responsive to an overload for operating the valve means momentarily to admit sufflcient fluid to the cylinder to actuate it to uncover said port, means biasing the contacts for reclosing, and means responsive to a reduction of fluid pressure in the container below a predetermined value for operating the valve more than momentarily so as to actuate the piston past said port to render the latch mean-s effective.

15. An automatic reclosing circuit breaker comprising, separable contacts, fluid actuated means for separating said contacts including fluid actuated brake means for limiting operation of the fluid actuated means and delaying reclosing of the contacts, vent means for said fluid actuated means for rendering said brake means effective at a predetermined separation of said contacts, and valve means responsive to a predetermined overload current for admitting fluid under pressure to said fluid actuated means.

16. An automatic reclosing circuit breaker comprising, separable contacts, fluid actuated means operable to separate said contacts, a container for fluid under pressure, valve mean operable to admit fluid from the container to the fluid actuated means, electroresponsive means having a movable part operable in response to an overload to actuate said valve means to admit fluid to the fluid actuated means, time delay means operable to delay movement of said movable part to effect actuation of said valve means, and pressure responsive means operable to render said delay means inefiective so long as the pressure in the container remains above a predetermined value.

17. An automatic reclosing circuit breaker 1;

comprising, separable contacts, fluid actuated means operable to separate said contacts, storage means for storing enough fluid under pressure to effect a plurality of operations of the fluid actuated means, valve means operable to admit fluid from the storage means to the fluid actuated means, solenoid means having a movable part operable in response to a predetermined overload current to operate the valve means, time delay means acting on the movable part to delay operation of the valve means, and pressure responsive means having a movable part operable in response to pressures in the storage means of greater than a predetermined amount to move in one direction and render the delay means inoperative, said pressure responsive means being operable in response to pressures in the storage means of less than a predetermined lower amount to move in the other direction to operate the valve means to effect sepaand latch means for the piston disposed beyond said port; a container for fluid under pressure disposed about the contacts, are chamber, cylinder and piston; valve means operable to admit fluid from the container to the cylinder through the arc chamber; solenoid means operable in response to an overload current of predetermined value through said contacts to operate said valve means; brake means on said piston having a fluid reservoir for storing fluid to effect operation of the brake means when the piston traverses said vent; means for biasing said contacts to efiect engagement upon separation; and means biasing said valve means to terminate the admission of fluid to the fluid actuated means.

19. An automatic reclosing circuit breaker comprising; separable contacts; an arc chamber surrounding the junction of said contacts; fluid actuated means for separating said contacts; means biasing said contacts closed; a container for fluid under pressure, said container being disposed about the arc chamber, contacts and fluid actuated means and disposed to contain suflicient fluid for a predetermined number of operations of the fluid actuated means; valve means for admitting fluid to the fluid actuated means from the container through the arc chamber; means responsive to a predetermined overload condition for operating said valve means; and brake means having a friction element disposed to enclose a pressure chamber subject to fluid pressure from the fluid actuated means for opposing the biasing means and delaying closing of the contacts following a separation.

JAMES M. WALLACE. ALBERT P. STROM.

References Cited in the file of this patent UNITED STATES PATENTS 

